Session Type: ACR Poster Session C
Session Time: 9:00AM-11:00AM
The presence of anti-citrullinated proteins antibodies (ACPAs) in RA is associated with a more aggressive disease phenotype and bone destruction. Synovial fibroblasts (SFs) are key players of both synovial inflammation and bone destruction in rheumatoid arthritis (RA). We aimed to invesigate the effect of ACPAs on synovial fibroblasts.
SFs were isolated from synovial tissue of RA patients (RA SFs) by enzymatic digestion. ACPA positive and negative IgGs were separated from plasma of RA patients and monoclonal ACPAs were generated from synovial fluid single B-cells. The effect of polyclonal and monoclonal ACPAs and appropriate negative controls was tested in migration scratch assays and adhesion assays by xCELLigence System Real-Time Cell Analyzer (ACEA bioscience). Light microscopy images were analyzed using NIH ImageJ to calculate migration index. Impedance-based signals were monitored every minute for1 hour, every 5 minutes up to 13 hours and every 15 minutes up to 36 hours. Inhibition of phosphoinositide 3-kinase (PI3K), G-protein coupled receptors, focal adhesion kinase (FAK) and peptidylarginine deiminases (PAD) inhibitor were tested in migration scratch assays in the presence or absence of the antibodies.
Polyclonal ACPAs but not others IgGs than ACPAs induced a 2.6±0.5 (mean±SD) fold increase in RASFs migration (p<0.05). ACPAs also induced a significant fold increase in RASFs adhesion of 1.3±0.1 (p<0.05). Similar effects were observed with one (D10), but not others two monoclonal ACPAs, with a fold increase of 2.4±0.4 (p<0.05) in migration index and 1.2±0.1 (p<0.05) in adhesion index.
G-protein coupled receptor blockade completely abolished ACPAs effects on RA SFs migration, while PI3K blockade decreased migration to a residual fold increase of 1.4±0.4 (mean±SD) and FAK blockade had no effect. Irreversible PAD blockade and pre-incubation of antibodies with citrulinated fibrinogen abolished ACPAs effects. No difference in either cytotoxicity or proliferation rate were observed between different treatments.
ACPAs directly mediate fibroblast migration and adhesion through a novel G protein coupled receptor and PAD-dependent mechanism. Our findings provide novel insights into the link between adaptive immunity and synovial fibroblasts.
To cite this abstract in AMA style:Sun M, Joshua V, Hensvold AH, Amara K, Malmström V, Wähämaa H, Catrina AI. RA-Associated Autoantibodies Promote Synovial Fibroblasts Migration and Adhesion through a Peptidylarginine Deiminases (PAD) Dependent Pathway [abstract]. Arthritis Rheumatol. 2015; 67 (suppl 10). https://acrabstracts.org/abstract/ra-associated-autoantibodies-promote-synovial-fibroblasts-migration-and-adhesion-through-a-peptidylarginine-deiminases-pad-dependent-pathway/. Accessed October 25, 2021.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/ra-associated-autoantibodies-promote-synovial-fibroblasts-migration-and-adhesion-through-a-peptidylarginine-deiminases-pad-dependent-pathway/